Muffin pan



FIG. 1 is a perspective view of a muffin pan, showing my new design;

FIG. 2 is a top plan view of the invention;

FIG. 3 is a bottom plan view of the invention;

FIG. 4 is a left-side elevational view of the invention, the right-side elevational view being a mirror image thereof; and,

FIG. 5 is a front elevational view of the invention, the rear elevational view being a mirror image thereof. 

I claim the ornamental design for a muffin pan, as shown and described. 